Factors Associated with Medication Adherence in Elderly Individuals with Tuberculosis: A Qualitative Study

Methods This qualitative study was conducted in two phases, using an integrative literature review and individual interviews. Studies were gathered without time restriction from MEDLINE databases, Institute for Scientific Information (ISI), Google Scholar, Scopus, and EMBASE, as well as national databases, including Scientific Information Database and Magiran. The findings of 38 studies that met the inclusion criteria were analyzed through the conventional content analysis method based on the ecological approach. After reviewing and forming the data matrix, purposive sampling was performed among healthcare professionals, elderly tuberculosis patients aged 60 and over, and family caregivers of elderly patients to conduct individual interviews. Data obtained from 20 interviews were analyzed using the directed content analysis method. After coding, the data from individual interviews were entered based on similarity and difference in the categories of data matrix obtained from the literature review. Results In general, the aforementioned codes were placed in four main categories, including individual factors (i.e., biological factors, affective-emotional factors, behavioral factors, cognitive factors, tuberculosis-related factors, and economic factors), interpersonal factors (i.e., patient's relationship with treatment team and family-related factors), factors related to healthcare service provider centers (i.e., medical centers' facilities and capacity building in healthcare service provider), and extraorganizational factors (i.e., social factors and health policymaking). Conclusion The results of this study showed that medication adherence in elderly patients with tuberculosis was a complex and multidimensional phenomenon. Therefore, society, policymakers, and healthcare providers should scrutinize the factors affecting medication adherence in this group of patients to plan and implement more effective interventions.


Introduction
One of the most important ways to control and eradicate tuberculosis is successful treatment [1], and the main determinant in a successful treatment is medication adherence [2][3][4][5][6][7]. Despite various interventions, such as directly observed treatment [4,8], tuberculosis medication nonadherence still occurs [9,10] and a signifcant number of tuberculosis patients do not have appropriate medication adherence [2,11]. Tuberculosis specialists have estimated the spectrum of medication nonadherence to be 20-100% [4].
Medication nonadherence in tuberculosis reduces the rate of successful treatment [12] and recovery [13]. In addition, it causes failure in treatment, prolonged hospitalization, and delay in treatment completion, and as a result of prolonged treatment process, there will be increased treatment costs, psychological complications [2,14], recurrence of the disease, increased risk of drug resistance, and increased death rates related to disease [8,11,[14][15][16][17]. Each patient with active tuberculosis causes the infection of 5-15 individuals in a year [18], and failure in the treatment and prolongation of the treatment process will, in turn, lead to the increased likelihood of tuberculosis prevalence in society and the increased burden of the disease [6,11,14,19].
Some studies have shown that nonadherence [20], poor adherence, and default treatment process are more common in elderly tuberculosis patients [21,22] to the extent that some scientifc evidences consider that the failure in eradicating tuberculosis results from treatment failure in the elderly group [8,23,24].
Te global frequency of tuberculosis in the elderly is three times [21,25], and related death rate is six times higher than nonelderly individuals [26]. It is expected that following demographic changes and the increase in number of elderly individuals, the incidence of tuberculosis will also increase in this age group [21]. As a result, the tuberculosis control in the elderly can afect tuberculosis prevention and control programs in all countries [25,27].
Given the importance of medication adherence in tuberculosis, especially in elderly patients, it is necessary to recognize the factors related to medication adherence and investigate them to empower tuberculosis eradication strategies [28]. Identifying these factors and carrying out appropriate interventions can improve medication adherence and subsequently that lead to more efective tuberculosis control [29] and help policymakers, healthcare providers, society, and patients in solving tuberculosisrelated problems [30].
Although numerous studies have been conducted about the factors associated with medication adherence in tuberculosis patients, there are few studies specifcally in the feld of the elderly [31,32]. Since disease manifestations, diagnoses, consequences, and treatments in the elderly are diferent from other age groups [27,33,34], it is necessary to consider the factors related to medication adherence in this group of patients separately.
Treatment adherence behavior is a complex and dynamic phenomenon and is related to a wide range of geographic, cultural [19], social, and economic factors [35,36]. Treatment adherence is not merely a medical phenomenon, and related psychological and social dimensions can be expected. Understanding such phenomena requires a holistic approach that can be achieved through qualitative studies. Te recent interest in the studies related to the qualitative approach in the feld of medication adherence confrms this important issue. Qualitative studies and paying attention to the opinions, perceptions, and experiences of patients and groups related to tuberculosis treatment lead to a better and deeper understanding of these factors [35,37] based on the context of a tuberculosis patient's life and the healthcare service provider system [38,39], better understanding and interpretation of fndings obtained from quantitative studies [11], clarifying the medication adherence phenomenon [40][41][42], and as a result facilitating interventions, empowering patients, and improving medication adherence [35].
According to the abovementioned conditions, the knowledge about factors afecting the medication adherence of elderly tuberculosis patients is limited, and qualitative studies play an important role in identifying and deeply understanding these factors. Terefore, the aim of this study was explaining the factors related to medication adherence based on the healthcare professionals, elderly tuberculosis patients, and their caregivers' experiences.

Study Design, Sample Size, and Sample Collection.
Te present study consisted of two parts. First, an integrative literature review [43] was carried out, and the data were analyzed based on conventional content analysis [44]. Te second part of the study was conducted based on the interviews with healthcare professionals (i.e., physicians and nurses), elderly tuberculosis patients, and family caregivers of the elderly. Furthermore, the directed content analysis method was used to analyze the data obtained from the interviews [44].
In the integrative literature review section, the literature search was conducted in November 2020 according to systematic review studies and without time restrictions. Te titles and abstracts of English and Persian articles were used using the keywords, including adherence, nonadherence, treatment nonadherence, medication adherence, medication nonadherence, concordance, tuberculosis, elderly, older individuals, aging, and old were used individually, in addition to MEDLINE databases (including PubMed and Ovid), Institute for Scientifc Information (ISI), Google Scholar, Scopus, EMBASE, and national databases, including Scientifc Information Database, Magiran, as well as national journals.
In addition, a manual search was performed by reviewing the references of the selected articles, and related articles were retrieved. Full-text research articles on medication adherence in tuberculosis (with quantitative and qualitative methods) were included in the study. First, the titles of the articles were examined, and duplicate articles were excluded from the study. Among the remaining articles, the abstracts of the articles that met inclusion criteria were independently reviewed by two members of the research team. Finally, 38 studies were analyzed. Te mixed methods appraisal tool (MMAT) (version 2018) was used to check the quality of the studies [45][46][47][48][49][50]. Based on the MMAT, all the studies had suitable quality to be included in the review. Te article selection process was implemented based on the PRISMA protocol ( Figure 1).
In the second part, after compiling the data analysis matrix obtained from the integrative literature review, individual interviews were conducted with the participants. Te participants were selected by purposive sampling including the healthcare professionals (i.e., physicians and nurses) who had the experience of working with tuberculosis patients; elderly tuberculosis patients who aged 60 and over with a defnite diagnosis of pulmonary tuberculosis, diagnosis as a new patient, passing at least one month since the start of treatment, the ability to communicate, no cognitive problem (according to the abbreviated mental test) [51], and referring to Dr. Masih Daneshvari Hospital clinic (As a reference center for tuberculosis in Iran) and health centers covered by Shahid Beheshti University of Medical Sciences, Tehran, Iran; as well as family caregivers of the elderly who were partially or fully responsible for caring an elderly TB patient for at least 6 months.
Individual and semistructured interviews were conducted during April and October 2021. After inviting the participants to attend the interviews and assuring them of information confdentiality, written informed consent was obtained. Te interviews were conducted in a private room at the infectious disease clinic or the patient's home or workplace. At the time of conducting the interview, the interview process was recorded with the subjects' permission. Te interviews continued until data saturation was reached. Te healthcare professionals had to answer the questions, such as "In your opinion, what individual, interpersonal, treatment system, and social factors can afect the use of medications in elderly tuberculosis patients?." Questions related to the patients and caregivers were designed more simply, for example patient related questions such as "Has it ever happened that you did not take your medicines as prescribed by the physician? Why?" Or "Can you explain what factors make it difcult for you to take medicines?;" besides a question such as "Is your patient facing a problem in taking his/her medications? Please explain." Was asked from their caregivers. Te interviews continued with asking follow-up and exploratory questions. 20 interviews with the participants were conducted and analyzed (Table 1).

Ethical Issues.
Te present study was a part of a PhD thesis and was approved by the Ethics Committee of the University of Rehabilitation Sciences and Social Health, Tehran, Iran. Necessary permits to conduct the research were obtained from the vice-chancellor of Research. All the subjects were free to participate or leave the study. In all stages of the project implementation, the principle of information confdentiality of the participants was observed.

Data Analysis.
In the integrative literature review section, conventional content analysis with the Elo and Kyngäs method (2008) was used for data analysis [44]. Te researcher used the ecological approach in this section to achieve a comprehensive view [52][53][54][55]. First, the fndings of the articles were examined, and the factors afecting medication adherence were extracted. Ten, data coding and factor classifcation were performed. Te analysis of this part of the study was used to produce the data analysis matrix of the second part.
In the second part of the study, after conducting each interview, the audio fle of the interview was listened several times. Finally, the interview transcript was prepared in a typed form. Simultaneously with the progress of the interviews, data analysis was performed with the directed content analysis method through the Elo and Kyngäs method [44]. For this purpose, the text of each interview was read several times to immerse in the data and gain a general understanding of the interview. Ten, coding was done and the codes obtained from each interview were entered based on similarities and diferences in the categories of the data matrix obtained from the literature review. Te codes that were not included in any of the categories of the data matrix formed new categories and subcategories using the inductive approach.

Results
In the frst part of the study, based on the ecological approach, the codes extracted from the studies were placed in three main categories, including individual, interpersonal, and extraorganizational factors. Te codes obtained from the interviews with the participants were also placed based on similarities and diferences in the categories of the matrix obtained from the literature review. Te codes that were not included in any of the categories of the data matrix formed new categories and subcategories using the inductive approach as follows (shown in gray in Table 2): Primary subcategories, including the polypharmacy, activities of daily living (ADL), instrumental activities of daily living (IADL), patient's personality, acceptance of illness, professional competence of the treatment team, educating the patient and caregiver by the treatment team, general characteristics of the family caregiver and family caregiver knowledge, and the main category of factors related to healthcare service provider centers.
In general, the codes obtained from the integrative literature review and individual interviews formed four main categories, including individual factors, interpersonal factors, factors related to healthcare service provider centers, and extraorganizational factors ( Table 2). Te subcategory of biological factors dealt with the individual characteristics afecting the medication adherence of the elderly tuberculosis patients. Te analysis of the data obtained from the literature review confrmed that the age [20,31,32,[56][57][58][59][60][61][62][63][64][65][66], gender [22,61,66], and comorbidity [21,57,60,67,68] afected the medication adherence of elderly tuberculosis patients. Te interviews also confrmed the importance of these factors and their impact on medication adherence. In addition, the participants' experiences in the interviews indicated the impact of the polypharmacy, activities of daily living (ADL), and instrumental activities of    Regarding age, the results of the studies were contradictory; however, most studies showed decreased medication adherence by age increasing [31,[56][57][58][59]. Te interviews with healthcare professionals also indicated less adherence in older ages. Te results of the review regarding the efect of gender on the medication adherence of elderly patients with tuberculosis were also contradictory; nevertheless, most studies demonstrated lower adherence in male patients [22,61]. A nurse with work experience in teaching patients about comorbidity and polypharmacy said:

Category of Individual
". . .Undoubtedly, the elderly do not take a large number of medicines and pills, or for example, they have problems, such as advanced rheumatoid arthritis; it is even difcult for them to take the pills out of their covers, or they have vision problems and cannot see their medicine well." Te patients believe that the ability to perform activities of daily living and instrumental activities of daily living is an important factor for tuberculosis medication adherence. In this regard, a 76-year-old female patient said: "I'm happy that God has given me the physical ability, and I am able to do the treatment afairs and take medicines as much as possible." Te subcategory of afective-emotional factors referred to afective and emotional factors. Te analysis of data obtained from the literature review confrmed that motivation for treatment [69,70], depression and anxiety [70,71], and patient's afections and feelings [66] afected the medication adherence of elderly tuberculosis patients. Te participants' experiences in the interviews indicated the impact of the patient's personality, and acceptance of illness on medication adherence behavior of elderly tuberculosis patients. Te 76-year-old female patient said: ". . .I believed that I should take medicine to get better and not be a burden on my children. My illness was a great sorrow for them and this hurt me." Te subcategory of behavioral factors referred to the patient's self-care ability [57,70], substance abuse [66,69,70], and the use of reminders for taking medication [72,73] [67,69,70,74,[76][77][78][79][80], and patient 's general knowledge [59,66,81]. Te interviews also confrmed the importance of these factors and their impact on medication adherence in elderly tuberculosis patients. One of the physicians in this regard said: . . ."Te efective interaction of the patient with the physician and the correct understanding of the physician's explanations about taking the medications are very important. We had elderly patients who understood the detailed explanations we gave them very well and cooperated with us." One of the physicians, regarding the patient's knowledge about tuberculosis and treatment, said: . . ."When a patient gets tuberculosis, he/she should understand the danger for him/herself and society. When the patient understands, he/she changes his/her behavior to escape from this danger and eliminates this threat. Te frst change in his/her behavior is the correct consumption of medications." Te results of studies on the efect of the patient's general knowledge and education on the medication adherence of elderly tuberculosis patients were contradictory [59,66,80]. In this regard, the majority of healthcare professionals believed that the education of the elderly afected tuberculosis medication adherence.
Te subcategory of factors related to the disease and antituberculosis treatment referred to the type of tuberculosis [21,22,61], characteristics of pharmacotherapy [57,66], response to treatment [70,75], and medication side efects [58,67,70] based on the literature review and participants' experiences in the interviews. Te prolonged tuberculosis treatment course is one of the factors afecting tuberculosis medication nonadherence [66]. One of the physicians said: . . ."I took medicine for a while, but I do not feel sick anymore, and I think I do not need medicine anymore." Te results of this study showed that the management of side efects of the patients was efective in the treatment continuation. In this regard, a 67-year-old female patient said: . . ."I could not take medicine, and I stopped it. I came to the hospital; they told me I should be admitted to see why the medicine bothered me. I was hospitalized for 12 days, and they gave me antiallergic medicine. Afterward, the tuberculosis medicines did not bother me anymore, and I took all the medicines." Te subcategory of economic factors referred to economic issues. Te analysis of the data obtained from the literature review and interviews confrmed that patient's fnancial ability [78,81] and the patient's employment [67,74,82] impact on medication adherence in elderly individual with tuberculosis. One of the family caregivers in this regard said: . . ."For a patient who does not have money, taking medicine does not make sense. He/she says that I do not have money, so I will not take medicine until I die." Te subcategory of relationship with the treatment team referred to the professional ethics of the treatment team [67,74,82] and trust in the treatment team [70,82] according to the available evidence based on the literature review. In addition to the abovementioned cases, the participants in the interviews emphasized the impact of the professional competence of the treatment team and educating the patient and caregiver by the treatment team. One of the essential codes extracted in the feld of professional ethics of the treatment team, which was mentioned in the literature review and interviews, was the establishment of proper communication between the treatment team and the patient [82]. One of the nurses in this regard said: . . ."I think it is crucial for the treatment team to accept the patient as a human being and establish a proper relationship with him/her." A 76-year-old female patient in this regard said:

. . ."My physician was very good. While he is paying attention to other patients, he also pays attention to me and answers my questions."
One of the pulmonologists about the professional competence of the treatment team said: . . ."After 24 years of work experience, I've found out whether the patient really had the necessary capacity to take the medicines or not and understand my training or needed more explanations and follow-up." A 76-year-old male patient about trust in the treatment team said:

. . ."I had an argument with a nurse in the clinic. Te same nurse came to the ward and did not let the physician examine me. I realized that the nurse had enmity with me, and I would not get better in that hospital. So, I left the hospital and discontinued my treatment."
One of the physicians about the importance of educating the patient said: . . ."It happens many times that a family member comes and insists that he/she must take this medicine by him/ herself and deliver it to the patient. Ten, we have to see if the caregiver has received the necessary training and transfer this training (regarding how to take medicine, medicine side efects, and when to come and let us know if the medicine causes complications) to the elderly in the correct way. All these are some of the problems we have in the treatment of elderly patients with tuberculosis." Te subcategory of family-related factors it refers to the characteristics of the patients' family members. Te review of studies showed the efect of the presence of a supportive family [66,69,70,74] on the medication adherence of elderly tuberculosis patients. Te experiences of the participants in the interviews showed that not only the supportive characteristics but also the family caregiver's general characteristics and knowledge infuence the medication adherence of this group of tuberculosis patients. An 86-year-old male patient in this regard said: Te subcategory of medical centers' facilities referred to responding to the patients' needs, centers' equipment, and resource adequacy. No study was identifed related to the aforementioned subcategory, and this subcategory was created based on the participants' experiences. One of the physicians in this regard said: . . ."Our centers are very crowded. Te elderly do not have the patience to sit in a long queue and they might not be referred to our centers at all." Another physician suggested: . . ."Tere should be special days to visit elderly tuberculosis patients. In this case, the physician or the relevant expert will examine the patient at ease. A tuberculosis patient is a time-consuming patient. On the other hand, an elderly patient does not understand the content and is not satisfed by explaining once." Some caregivers pointed to the lack of proper response of medical centers following the coronavirus disease 2019 (COVID-19) pandemic. One of the caregivers said in this regard: . . ."Te main problem is making an appointment for visits and receiving medicines. After the onset of the COVID-19 pandemic, it has become very difcult to make an appointment." One of the pulmonologists about the resource adequacy said: . . ."Currently, when we are dealing with COVID-19, unfortunately, chronic and infectious diseases, such as tuberculosis, are on the sidelines because our health and treatment resources are limited." A 67-year-old male patient also in this regard said: . . ."I referred to the clinic to receive medicine, but this month, the medicine had not come due to the COVID-19 pandemic. Terefore, I stopped taking my medicines for 2 days." Te subcategory of capacity building in healthcare service provider was also created only based on the codes obtained from interviews with the participants. Tis subcategory referred to educating the staf, monitoring the health of the staf, and motivating the staf. In this regard one of the physicians said: . . ."In order to achieve the desired result in the treatment of tuberculosis, we should increase the awareness of the staf regarding the issues of the elderly patients." Another physician suggested: . . ."In order to be successful in the tuberculosis treatment, we need to take care of both physicians and nurses and have special privileges to work in the wards related to tuberculosis." 3.4. Category of Extraorganizational Factors. Te main category of extraorganizational factors was obtained from the subcategories of social factors and health policymaking.
Te subcategory of social factors referred to the tuberculosis stigma [37,67,69,70,75,80,83], belief in traditional treatment [79], social development [19,66,74,84], and social support [69,70,74] according to the available evidence based on the literature review. Te participants' experiences in the interviews also emphasized the aforementioned items. One of the physicians about stigma said: . . ."Te tuberculosis stigma leads to the rejection of the patient by the family, causes emotional and mental problems, and afects taking medications." One of the caregivers also in this regard said: . . ."I did not tell a word the people around me about my husband's tuberculosis. Anyone who asked, we said that he had a cold and his lungs were infected. If we say that he has tuberculosis, people's behavior will change. People will run away from him, and as a result, his mood will deteriorate, and he might not be able to continue treatment." One of the caregivers about taking traditional medications said: . . ."I used herbal medicines to relieve my father's pain and cough. Finally, this forced me to take him to the hospital and caused delayed treatment." One of the nurses about social development said: . . ."It is difcult for the elderly to go to health centers. Some elderly individuals have to use the bus to reach the hospital. Due to the problems of public transportation, the elderly patients might often not refer to the health centers." One of the physicians, regarding the efect of place of residence on medication adherence, said: . . ."Elderly individuals with tuberculosis who live in urban areas have better medication adherence." Te subcategory of health policymaking based on the evidence from the literature review referred to the existing treatment protocols [61,75,76,85] and the level of insurance coverage [66,67,81]. Te participants' experiences also confrmed the aforementioned issue. One of the physicians in this regard said: 8 Canadian Journal of Infectious Diseases and Medical Microbiology

. . ."In my opinion, the implementation of directly observed treatment is critical and efective in the medication adherence of elderly patients with tuberculosis."
One of the pulmonologists in this regard said: . . ."COVID-19 pandemic has afected tuberculosis treatment policies. Tuberculosis diagnosis has decreased. Patients with tuberculosis do not refer to the treatment centers or refer late. Physicians do not pay attention to the differential diagnosis of tuberculosis, and their main focus is on the diagnosis and treatment of COVID-19." Te results of the literature review about the efect of health insurance on the medication adherence of elderly patients with tuberculosis were contradictory [66,67,81]; however, all the interviewed groups pointed to the positive role of insurance in medication adherence.

Discussion
Tis qualitative study was frst conducted to identify the factors afecting the medication adherence of elderly tuberculosis patients in Iran. Te results of this study showed that medication adherence in elderly tuberculosis patients is a complex and multidimensional phenomenon with the related factors that are placed in four main categories of individual factors, interpersonal factors, factors related to healthcare service provider centers, and extraorganizational factors.
Based on the fndings of the present study, the most efective factors in medication adherence were placed in the main category of individual factors and subcategories of biological factors, afective-emotional factors, behavioral factors, cognitive factors, factors related to tuberculosis, and economic factors. Te results of the present study suggested a relationship between the age of elderly tuberculosis patients and medication adherence; accordingly, elderly patients with older age had less medication adherence. Kalhori's study in Iran showed that the probability of failure in tuberculosis treatment was higher in the elderly [86]. Medication nonadherence is one of the main factors in failure in tuberculosis treatment [2,14]. Terefore, it is important to pay special attention to elderly patients with tuberculosis in countries, such as Iran.
Te results of this study showed that the presence of comorbidity reduced medication adherence in elderly tuberculosis patients. Aging accompanies comorbidity, increased required medications and more complex treatment regimens [42], and drug interactions due to polypharmacy [8]. Consequently, the presence of comorbidity can also afect the continuation of the antituberculosis treatment [87].
Te results of the present study showed that afective and emotional factors infuenced the medication adherence of elderly tuberculosis patients. In addition, the fndings of the review section of the present study indicated less medication adherence in elderly tuberculosis patients and depression. Depression is a common disorder in patients with tuberculosis that causes adverse treatment outcomes [88,89]. In a study, Koyanagi et al. depicted that depression negatively afected the self-care process in patients with tuberculosis [89].
In this study, the efect of treatment response on medication adherence was inconsistent. In general, about 2 weeks after starting the treatment, the symptoms of numerous patients improved. Terefore, symptom improvement might be an obstacle to continue the treatment [70]. In a study on nonelderly patients with tuberculosis, feeling better as a result of treatment was also related to medication nonadherence [90].
Side efects due to tuberculosis medications are among other obstacles to continue the treatment [91]. Physiological changes, comorbidity, polypharmacy, and the possibility of side efects caused by tuberculosis medications increase by age [8]. In various studies, the side efects of tuberculosis medications were higher in the elderly [92][93][94][95]. Terefore, in the treatment of an elderly individual with tuberculosis, the possibility of showing side efects and their correct management should always be considered.
In this study, poverty, the fnancial burden caused by treatment, and loss of job and occupational opportunities were among the factors of medication nonadherence in elderly tuberculosis patients. Various studies have shown that tuberculosis is related to poverty [90,96]. Poverty is an obstacle to the successful implementation of tuberculosis control programs [97]. Poor individuals, especially the elderly in the developing countries, face more obstacles for receiving healthcare and treatment [18,97]. In Carlsson's et al. qualitative study, nurses mentioned poverty and lack of adequate nutrition as the reasons for discontinuing tuberculosis treatment [98]. In Gebreweld's et al. study, losing a job and the resulting fnancial problems following the diagnosis of tuberculosis in the elderly are associated with nonadherence to medication [78].
Te results of this study demonstrated that the relationship of elderly tuberculosis patients with the treatment team and family members afected medication adherence. Te proper relationship between the elderly patient and the members of the treatment team (i.e., physicians and nurses) is an essential principle in disease management and treatment. Moreover, providing sufcient information and educating patients are necessary for proper communication, which afects medication adherence [99]. Studies conducted on individuals with chronic diseases also showed the efect of the relationship between the patient and the physician on medication adherence [100]. In a study on the elderly with a disease other than tuberculosis, Ben-Natan and Noselozich showed a positive relationship between the patient's trust in physician's professional ability and their medication adherence [101].
Tuberculosis patients need proper education regarding tuberculosis treatment [102]. However, the results of the present study showed that according to some physicians and nurses, providing more information to elderly tuberculosis patients made these patients confused and worried; as a result, they did not provide the patients with enough information. Various studies also showed the presence of a negative attitude toward the elderly in healthcare environments. Ageist stereotypes, judgments, and discrimination are important barriers to health equity, in addition to the quantity and quality of care provided for the elderly. Terefore, it should be noted that discrimination based on age afects the clinical practice and decision-making of healthcare providers [103].
Te health culture of tuberculosis patients is afected by the information received from family, friends, neighbors, and other members of society [104]. Although no specifc study was carried out on the elderly in this regard, the results of other studies revealed the efect of family relationships on the medication adherence of patients with tuberculosis [105,106]. In a study on nonelderly patients with tuberculosis, Liefooghe and Muynck also suggested that one of the principles of successful treatment of tuberculosis in the intensive phase was encouraging the patient to continue treatment by family members [105].
Te results of this study indicated the infuence of factors related to healthcare service provider centers on the medication adherence of elderly tuberculosis patients. To date, no study has been conducted on the efect of the aforementioned factors on the medication adherence of elderly tuberculosis patients; nevertheless, the results of the present study showed that the medical centers' facilities and capacity building in healthcare service provider, including motivating the medical personnel, play an important role in the medication adherence of elderly tuberculosis patients. Te results of Dimitrova's et al. study on nonelderly patients with tuberculosis also showed that healthcare workers' insufcient salary and lack of motivation are among important obstacles to tuberculosis treatment adherence [107].
Te results of the present study illustrated that extraorganizational factors, including social factors and health policymaking, also afected the medication adherence of elderly tuberculosis patients. Based on the fndings of this study, the culture of society is one of the important and infuential social factors in the medication adherence of elderly individuals with tuberculosis. One of the important cultural factors is the stigma caused by tuberculosis. Stigma is one of the obstacles to the timely referral of the patient to the treatment centers, and as a result of treatment discontinuation, which has been mentioned in various studies, has negative efects on medication adherence [107][108][109][110][111]. Tuberculosis is an infectious and threatening disease. Terefore, there are widespread negative perceptions about this disease. Most individuals consider tuberculosis a social disease and limited to specifc population groups with antisocial behaviors [107]. In Woith's and Rappleyea study, negative feelings about tuberculosis were related to stigma, and the elderly had more negative feelings about tuberculosis [112].
In the current study, the use of traditional treatments was another factor infuencing the medication adherence of elderly individuals with tuberculosis. In other studies, patients' turning to traditional tuberculosis treatments was also related to medication nonadherence [30,91,113]. Te belief in the efectiveness of traditional medications, the shorter period of traditional treatments, and the lower costs of these types of medications are the reasons for patients to turn to traditional treatment [30]. In Gele's et al. study, difcult access to medical centers, especially in vulnerable patients such as the elderly, was one of the factors for choosing traditional treatments [113]. Terefore, in the treatment process of an elderly tuberculosis patient, the possibility of using traditional medications and the factors afecting this choice should always be taken into consideration.
Te results of this study depicted the efect of social support on the medication adherence of elderly tuberculosis patients. In general, the elderly need social support more than other age groups [114], and those who live alone have more problems taking their medications [115]. In a study, Lu et al. suggested that the social isolation of elderly patients with chronic diseases had a negative efect on the social support and medication adherence of the elderly [116].
Te fndings of the present study indicated the efect of health insurance on the medication adherence of elderly tuberculosis patients. Dong's et al. study showed that using an insurance-based approach increased hospital admissions, outpatient visits, and drug use in poor patients with tuberculosis [97]. Since poverty, fnancial dependence of family members on pensions for the elderly, and lack of access to healthcare are common problems of the elderly, especially in the developing countries [18], it can be expected that paying special attention to health insurance coverage for elderly patients with tuberculosis is very essential to promote medication adherence in this age group.
Tere were some limitations for the present study due to the impossibility of access to some relevant texts, especially full texts, and the need for English studies. Te study sampling was performed during the COVID-19 pandemic, which limited the interviews, although it was tried to conduct the interviews by following the protocols and through phone calls, if necessary. One of the strengths of the present study is the integrative literature review. Te integrative literature review not only brings together scattered data and creates a basis for conducting specifc studies on the elderly but also provides the possibility of entering studies with quantitative and qualitative methods to the review [43] and develops a comprehensive understanding of the problems related to healthcare and health policymaking [43].
Another strength of the current study is conducting individual interviews with physicians, nurses, elderly tuberculosis patients, and their family caregivers. Tis part of the study led to a better and deeper understanding of the factors afecting medication adherence in elderly tuberculosis patients.

Conclusion
Despite numerous attempts, a large number of tuberculosis patients, especially the elderly, have not yet had complete medication adherence. Terefore, the identifcation of the factors related to medication adherence and implementation of appropriate interventions in this age group will be an important step towards maintaining and improving the health of tuberculosis patients and other members of the society. Te results of the present qualitative study illustrated that medication adherence in elderly tuberculosis patients was not limited to physical and biological factors; however, it was a multidimensional phenomenon and was infuenced by a wide range of individual factors, interpersonal factors, factors related to healthcare service provider centers, and extraorganizational factors. Terefore, it is necessary for society, policymakers, and healthcare providers to have a more comprehensive look at the factors afecting medication adherence in this group of patients to plan and implement more efective interventions.

Data Availability
Te data are available and there is no restriction on additional information.

Conflicts of Interest
Te authors declare that they have no conficts of interest in this study.